Fluoride in water
Fluoride may be added to the water supply so it is at a concentration between 0.7 parts per million (ppm) and 1.0 ppm. This is the optimal concentration to help prevent tooth decay. Fluoride makes teeth more resistant to decay by strengthening tooth enamel, inhibiting the growth of the bacteria on teeth that cause dental caries and also by repairing the early stages of tooth decay.
For more information please view the Ministry of Health (MOH) website.